Treatment of hydrocarbon oils



Sept. 18, 1934. G. EGLOFF TREATMENT OF HYDROCARBON OILS Filed March 16, 1951 lnHl l nnv I I I I b l atented Sept. 18, 193 3 TREATMENT OF HYDROCARBON GHLS Gustav Egloli, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, 111., a corporation of South Dakota Application March 16, 1931, Serial No. 522,870

3 Claims.

This invention relates to the treatment of hydrocarbon oils and refers more particularly to the conversion of relatively heavy hydrocarbon oil mixtures into mixtures of lower boiling point 5 range, containing substantial amounts of gasoline hydrocarbons.

More specifically, the invention contemplates the provision of a process whereby the ordinary decomposition reactions characteristic of the cracking of hydrocarbon oils are modified to produce products of a morerefined and stable nature containing lower amounts of sulfur and polymerized substances of a gummy nature. It is characteristic of cracking reactions that, while the initial decompositions produce reactive hydrocarbon residues on account of the splitting ctr of hydrogen from the original molecules, continuance of the reactions to a point corresponding to commercial yields of motor fuel permits the recombination of many of these residues to produce high molecular weight condensation products. These secondary reactions, tending to reduce the over-all yields and limit the quality of the final product of desired boiling point range are very objectionable. In addition, sulfur liberated either as hydrogen sulfide or in combination with transient radicals, tends to become fixed during the course of the recomposition reactions, so that its removal from the final product is difficult without the employment of prohibitive amounts of treating agents. The unsaturated compounds remaining in the final fractions of motor fuel boiling point range contribute to the instability of the product, in that they tend to absorb oxygen from the air under the influence of light, forming colored compounds and a resultant lower sales value of the product.

It is among the aims and objects of the present invention to provide a process which will en- 4 able the production of cracked motor fuel in substantially higher yields and of better quality than that obtainable by ordinary commercial operations.

In a more specific embodiment of the invention, controlled quantities of magnesium chloride solutions may be introduced into the process at advantageous points in the reactions and fractionating zones of the system. Small quantities of air may also be admitted to the system. Raw

oil charging stocks may be fed in admixture with reflux condensates from the process to a heating zone of the process for conversion therein, either directly or after contact and heat exchange relationship with the vapors undergoing treatment in a fractionation zone. Prior to the introduction of said raw oil changing stock and reflux condensate into said heating element, magnesium chloride solutions, with or without small amounts of air, may be introduced into said charge, and after the desired conversion within said heating on element, the heated products may be introduced into an enlarged vaporizing or reaction zone wherein further reactions occur, and heavy carbonaceous residues and vapors separate. Further amounts of chloride solution may be added 05 to the oil under treatment prior to its introduction into said reaction zone. The evolved vapors from said reaction zone may be passed to suitable fractionating devices for further segregation and separation into vapors approximating the desired boiling point range, and further amounts of the treating solution may be introduced into the vapors leaving said fractionating zone, together with small amounts of air, prior to their final cooling, condensation and collection.

Other and further objects and advantages of the invention will become apparent from the following description and accompanying diagrammatic drawing illustrating one form of apparatus in which the invention may be carried 30 out.

Referring to the drawing, raw oil charging stock, typified by such high boiling hydrocarbon mixtures as the residue from the topping of crude oils, or heavy mixtures produced from coal, shale, or the like may be taken by a pump 3 from a line 1, controlled by valve 2, and discharged either into a line 4, controlled by valve 5, or into a line 4, controlled by valve 5. In the first event, the raw oil will be discharged into a fractionator 26, typical of any conventional form of equipment, wherein hydrocarbon oil vapors from a cracking operation may be separated into their lighter and relatively heavy, insufiiciently converted components or reflux condensates. The raw oil may be introduced into the upper portion of said fractionator, passing substantially countercurrent therethrough to the vapors under treatment, serving to preheat the raw oil charging stock and stripping the same of any light portions thereof, while condensing the heavier, insufliciently converted portions of said vapors in the resultant heat exchange. The preheated ra'w oil and reflux condensates collect in the lower portion of said fractionator and may be withdrawn therefrom through a line 27, controlled by valve 28, leading to said line 4' in communication with a line 6, controlled by valve '7. The mixture of preheated raw oil and reflux conden sate and/or relatively cold fresh charging oil and 110 reflux condensate from said fractionator may be taken from said line 6 by a pump 8 which pumps the combined feed into a heating element 16, disposed in a suitable through a line 9, controlled by valve 10.

Prior to the introduction of the combined feed into the heating element, a solution of magnesium-chloride may be introduced into said feed line 9 from a line 14, controlled by valve 15. Line 14, in turn, communicates with and receives the discharge from a. pump 13, taking suction on a line 11, having a valve 12, leading from a source of reagent supply (not shown) In addition to the introduction of the solution of magnesium chloride into said feed line 9, controlled amounts in relatively small proportions, of air may be introduced into said line through a line 44, controlled by valve 45, receiving its supply of air from a pump or compressor 41 in communication with a source of supply (not shown) through a line 39, controlled by valve 40.

During the passage of the combined feed of raw oil and reflux condensate, chloride solution and air through said heating element 16, suitable conversion conditions of temperature and pressure are maintained therein, such conversion conditions being dependent upon the degree of conversion desired and the nature and characteristics of the particular oil under treatment. These temperatures may be of the order of about 750 to 1000 F., while a pressure of from to 500 pounds may be utilized, corresponding to the temperature. During the passage of the combined mixture through said heating element and under the conversion conditions utilized, reactions characteristic of the invention are initiated, leading, in general, to the production of oils typical of the cracked products of petroleum, except that the sulfur content and degree of unsaturation are less. Under the temperatures and pressures employed to crack the hydrocarbons, the magnesium chloride solution decomposes with water to form magnesium hydroxide and hydrochloric acid, the former acting as a desulfurizing agent, and the latter partially saturating and chlorinating the unsaturated radicals.

After subjection to the desired conversion conditions within heating element 16, the heated products are discharged therefrom through a line 18, controlled by valve 19, and introduced into an enlarged reaction chamber 20, maintained under substantially the same pressure as said heating zone. A sufiicient time period of retention of the heated products within said reaction zone is permitted, in order that the reactions commenced within said heating element may progress to completion, as well as permit separation of the relatively heavy residual products from the lighter, vaporous products of reaction.

Prior to the introduction of the heated products into said reaction zone from heating element 16, additional controlled amounts of chloride solution may be introduced into said highly heated products during their passage through the transfer line 18 by means of a branch line 48, controlled by valve 49, in communication with a line 46, controlled by valves 47 and 51, leading from said line 14 through which the chloride solution is introduced into the combined feed line 9, previously described.

The heavy, residual products of reaction may be withdrawn from chamber 20 for utilization as fuel or passed to storage, as desired, through a line 21, controlled by valve 22; while the heavy, carfurnace 17,-

be separated from the through a line 29, controlled by bonaceous deposits accumulating within said chamber may be removed through a man head 23, such residual liquid, carbonaceous solids, or semisolid products containing material amounts of magnesium sulfide or oxide. Vapors evolved within reaction chamber 20 may pass through a line 24, controlled by valve 25, and introduced through said line into fractionator 26 for further treatment, as previously described, in order that their lighter, desired boiling point fractions may heavier, insufliciently converted components, the latter being subjected to retreatment in the heating element 16 on discharge from said fractionator 26 through line 27, as previously described.

After suitable fractionation, the lighter desirable vapors from fractionator 26 are withdrawn valve 30 to a suitable condenser 31. Further controlled quantities of magnesium chloride solution may be introduced into said vapors through line 46, previously described, which is also in communication with said line 29. This may be accomplished by suitable manipulation of the valve 51 interposed in said line 46. In addition, air may be introduced into said vapor line 29 by means of a line 42, controlled by a valve 43, communicating with pump 41 taking suction from a source of described.

In condenser 31 partial liquefaction is effected, the condensed liquids and fixed gases passing through line 32, controlled by valve 33, to a suitable receiver 34 wherein said liquids and gases separate. Fixed gases may be withdrawn from said receiver through a line 35, controlled by valve 36, while liquid accumulations within said receiver may be withdrawn through a line 37, controlled by valve 38.

If desired, a lower pressure may be employed within the fractionator 26 in order that vaporization may be aided, and a corresponding lower pressure may be utilized in the receiver and condenser portions of the system.

As a specific example of the results obtainable and the conditions of operation in an adaptation of the process of my invention, the following is illustrative:

When a 20 gravity California residuum is cracked by a simple application of heat and pressure and without the addition of the reagents comprised within the scope of the invention, there is produced a yield of hydrocarbons of motor fuel boiling point range of approximately 55% by volume of the oil processed. These low boiling hydrocarbons are of such a nature as to require considerable subsequent chemical treatment before they are saleable in the light of commercial specifications. The color is usually a pale yellow; the gum content of the order of 500 mg. per 100 c. c.; the sulfur content as high as 0.3% or higher, and the stability of the product, when exposed to air and light, very poor.

When the same residuum is cracked under the same conditions of temperature and pressure, but with the addition of concentrated magnesium chloride solution in the amounts of approximately 3% of the oil cracked, the quantity of gasoline boiling point hydrocarbons produced may be increased to 57 or 58%, and the quality improved to a degree requiring greatly reduced quantities of chemicals for the production of a motor fuel meeting current specifications. For example, such a distillate, after treatment with sulfuric acid at the rate of 5 pounds of 66 B. acid per barrel of raw distillate, will yield, upon redistillation with steam a gasoline of 30 color on the Saybolt scale;

pp as previously V a gum content of only 20 mg., and a sulfur content of less than 0.1%. The color stability will be such that less than 5 points are lost upon 4 hours exposure to sunlight.

I claim as my invention:-

1. In the conversion of hydrocarbon oils wherein the oil is subjected to gasoline-producing cracking conditions of temperature and pressure, the method which comprises adding magnesium chloride to the oil undergoing cracking and reacting the same with water in the presence of the oil to form a suficient quantity of magnesium hy- 

